C++ atan2()用法及代碼示例

atan2()是C++ STL中的內置函數，它返回(y /x)的正切逆，其中y是y坐標的比例，x是x坐標的比例。數值介於– $\pi$ 和 $\pi$ 代表角度 $\theta$ (x，y)點和正x軸的角度。它是X軸正方向與點(x，y)之間的逆時針角度(以弧度為單位)。

用法:

atan2(data_type y, data_type x)

參數：該函數接受下麵描述的兩個強製性參數：

y –此值指定y坐標。
X -此值指定x坐標。

參數可以是double，float或long double數據類型。

返回值：該函數返回介於– $\pi$ 和 $\pi$ 代表角度 $\theta$ (x，y)點和正x軸的角度。它是X軸正方向與點(x，y)之間的逆時針角度(以弧度為單位)。

以下示例程序旨在說明atan2()函數：

示例1:

// CPP program to demonstrate the atan2() 
// function when both parameters are of 
// same type 
#include<bits/stdc++.h> 
using namespace std; 
  
int main() 
{ 
    double x = 10.0, y = 10.0, result; 
    result = atan2(y, x); 
  
    cout << "atan2(y/x) = " << result 
         << " radians" << endl; 
    cout << "atan2(y/x) = " << result * 180 / 3.141592 
         << " degrees" << endl; 
  
    return 0; 
}

輸出：

atan2(y/x) = 0.785398 radians
atan2(y/x) = 45 degrees

示例2:

// CPP program to demonstrate the atan2() 
// function when both parameters are of 
// different types 
#include <bits/stdc++.h> 
using namespace std; 
  
int main() 
{ 
    double result; 
    float x = -10.0; 
    int y = 10; 
    result = atan2(y, x); 
  
    cout << "atan2(y/x) = " << result 
         << " radians" << endl; 
    cout << "atan2(y/x) = " << result * 180 / 3.141592 << " degrees" << endl; 
  
    return 0; 
}

輸出：

atan2(y/x) = 2.35619 radians
atan2(y/x) = 135 degrees

示例3:

// CPP program to demonstrate the atan2() 
// function when y/x is undefined 
#include<bits/stdc++.h> 
using namespace std; 
  
int main() 
{ 
    double x = 0.0, y = 10.0, result; 
    result = atan2(y, x); 
  
    cout << "atan2(y/x) = " << result 
         << " radians" << endl; 
    cout << "atan2(y/x) = " << result * 180 / 3.141592 
         << " degrees" << endl; 
  
    return 0; 
}

輸出：

atan2(y/x) = 1.5708 radians
atan2(y/x) = 90 degrees

示例4:

// CPP program to demonstrate the atan2() 
// function when both parameters are zero 
#include<bits/stdc++.h> 
using namespace std; 
  
int main() 
{ 
    double x = 0.0, y = 0.0, result; 
    result = atan2(y, x); 
  
    cout << "atan2(y/x) = " << result 
         << " radians" << endl; 
    cout << "atan2(y/x) = " << result * 180 / 3.141592 
         << " degrees" << endl; 
  
    return 0; 
}

輸出：

atan2(y/x) = 0 radians
atan2(y/x) = 0 degrees

錯誤和異常：當字符串或字符作為參數傳遞時，該函數不返回任何匹配函數來調用錯誤。
示例5:

// CPP program to demonstrate the atan2() 
// errors and exceptions 
#include<bits/stdc++.h> 
using namespace std; 
  
int main() 
{ 
    double x = 0.0, y = 10.0, result; 
    result = atan2("1", x); 
  
    cout << "atan2(y/x) = " << result << " radians" << endl; 
  
    cout << "atan2(y/x) = " << result * 180 / 3.141592 
         << " degrees" << endl; 
  
    return 0; 
}

輸出：

prog.cpp:9:26: error: no matching function for call to 'atan2(const char [2], double&)'
     result = atan2("1", x);

相關用法

注：本文由純淨天空篩選整理自pawan_asipu大神的英文原創作品 atan2() function in C++ STL。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。